Laryngoscopes are in common use for the insertion of endotracheal tubes into the tracheas of patients during medical procedures. Laryngoscopes comprise a handle which remains outside the patient's oral cavity, for manoeuvring the laryngoscope during a procedure, and an insertion section which is extended into a patient's oral cavity, towards the larynx, in use. A light source and imaging apparatus, such as a series of mirrors and/or prisms, or a video camera, are provided towards the distal end of the insertion section to enable the patient's trachea to be viewed by a user during the intubation procedure. The insertion section may be an integral part of the laryngoscope or detachably retainable on a laryngoscope body portion which comprises the handle. A laryngoscope or detachably retainable insertion section may be reusable or disposable. Reusable video camera apparatus may be used with a reusable or disposable laryngoscope body portion and a reusable or disposable insertion section. A laryngoscope, including video camera apparatus, may be entirely disposable.
Within this specification and the appended claims, the inferior surface is the surface of an insertion section which faces the patient's tongue in use. The opposite surface is referred to as the superior surface. Words such as inferior, inferiorly, superior and superiorly are used in corresponding senses. The words distal and distally refer to being towards the end of the insertion section which extends towards a patient's trachea in use and the words proximal and proximally refer to being towards the person carrying out intubation in use.
In order to carry out intubation by traditional methods, using a traditional laryngoscope, such as a Macintosh laryngoscope, an intubater holds the laryngoscope in one hand and a sterile endotracheal tube in the other hand. Endotracheal tubes typically include a gentle curve and the tube is orientated to curve in the same sense as the patient's airway. The laryngoscope is then inserted into a patient. Once sight of the larynx has been achieved, the endotracheal tube is inserted using the other hand, along the curved arc of the tube. This two step procedure, requiring insertion of the laryngoscope and then an endotracheal tube, has been used successfully for many years, but it would be preferable to reduce the manual complexity of the task to facilitate rapid intubation.
It has been proposed to provide laryngoscopes which include a tube guide which can detachably retain and guide an endotracheal tube whilst the insertion section is introduced into a patient's airway. For example, WO 04/073510 (Gandarias) discloses a laryngoscope insertion section having a tube guide which extends laterally from an elongate member which contains apparatus to provide an image of a patient's larynx in use. Once the laryngoscope is in place and a clear view of the larynx has been obtained, an endotracheal tube within the guide is advanced into a patient's larynx whilst the larynx and advancing tube are monitored visually. The endotracheal tube can then be detached from the insertion section whilst the insertion section remains within a patient and the insertion section can be removed, leaving the endotracheal tube in place.
An advantage of providing a tube guide which can retain and guide an endotracheal tube is that the endotracheal tube is introduced into the airway at the same time as the laryngoscope, potentially speeding up intubation. Conceivably, a nurse or other member of support staff could insert the endotracheal tube into the tube guide and hand the laryngoscope with retained tube guide to the intubater, or leave it where the intubater can readily pick it up, speeding up intubation. However, with the laryngoscope disclosed in WO 04/073510, the proximal end of an endotracheal tube (i.e. the end which will remain outside a patient's airway in use) is not controlled, increasing the overall volume occupied by the laryngoscope and retained endotracheal tube and presenting a cumbersome appearance.
A further disadvantage of the laryngoscope disclosed in WO 04/073510 is that the proximal end of a retained endotracheal tube, which is not retained within the tube guide, is displaced laterally by the handle, bending the endotracheal tube laterally and increasing the difficulty of inserting the endotracheal tube.
As the endotracheal tube is retained in a deep groove throughout the tube guide, so that the endotracheal tube is not exposed on the surface of the tube guide, it can only be manipulated by grabbing the proximal end and pushing the tube. Thus, only a limited amount of control is possible. This problem is compounded in the laryngoscope disclosed in U.S. Pat. No. 6,655,377 (Saturn Biomedical), which has a handle that engages with a received endotracheal tube by including a straight through-bore through which a retained endotracheal tube extends in use. The endotracheal tube within the handle is not exposed on the surface of the handle and an intubater must reach quite far back, proximally of the handle, to manipulate a retained endotracheal tube.
Furthermore, known laryngoscopes with tube guides retain an endotracheal tube in a generally J-shaped configuration. This has two significant disadvantages. Firstly, the insertion of a J-shaped insertion section into a patient's oral cavity is reasonably difficult. A J-shaped insertion section normally must be tilted backwards and forwards during insertion to insert the distal end, manipulate the patient's anatomy and obtain a good view of the patient's larynx. It is preferable to provide a laryngoscope which can be more readily inserted. Secondly, this arrangement means that, when the endotracheal tube is pushed forward to advance the tube, a force is developed on the superior side of the tube guide where the endotracheal tube bends from being substantially straight to curved, which increases friction.
A still further disadvantage of known laryngoscopes with J-shaped insertion sections is that the method of inserting the laryngoscope and advancing the endotracheal tube is quite different to the traditional methods employed by intubaters using generally curved insertion sections that do not require multiple positioning manoeuvres which leave the intubater's other hand free to manoeuvre the endotracheal tube. It would be preferable to provide a laryngoscope including a tube guide which enabled intubaters to transfer the skills they have learned when using traditional laryngoscopes, such as Macintosh laryngoscopes, such as the hand motion required to move a curved tube along the curved path of a tube.
Accordingly, the invention aims to provide an improved laryngoscope which reduces or avoids one or more of the abovementioned disadvantages of known laryngoscopes.